ICD-10	DSM-IV-TR
F44 Dissociative (conversion) disorders	300 Dissociative disorders
F45 Somatoform disorders	300 Somatoform disorders
F45.0 Somatization disorder	300.81 Somatization disorder
F45.2 Hypochondriacal disorder	300.7 Hypochondriasis
F45.4 Persistent somatoform pain disorder	307.80 Pain disorder

For clarity, dissociative disorders will be described here separately from the conversion disorders. However, both dissociative and conversion disorders are usually temporarily related to a trigger and are of sudden onset, the links between psychological stress and resulting symptoms are not consciously known to the patient, and both are increased in females, in those under age 40 and those with vulnerable personalities.

Dissociative disorders

These are characterized by a psychogenic (psychologically caused)alteration in an individual’ state of consciousness or personal identity. Table 11.1 summarizes the description of dissociative disorders given in ICD-10.

Dissociation is a state where two or more mental processes coexist without becoming integrated. Emotional conflict and distress are thus segregated from normal consciousness, as in dissociative amnesia, or even to a separate distinct personality, which may take control of the person’ behaviour,as in multiple personality disorder. Historically, it was Janet who particularly emphasized the defence mechanism of dissociation following traumatic experiences in cases of hysteria. Doubts, however, remain about the definition and measurement of dissociation.

Dissociative amnesia

In this condition, the severity of loss of memory (whether partial or complete) for recent events of a traumatic or stressful nature contrasts with the otherwise very good preservation of other cognitive functions and the individual’ ability to utilize memories that are not of a personal nature. Complete recovery may occur within a few days once the precipitating stress is removed. In contrast to amnesia of organic aetiology, dissociative amnesia may respond to anxiolytic medication. Included in the differential diagnosis would, of course, be transient global amnesia due to temporal lobe ischaemia caused by vertebrobasilar insufficiency.

Classically, in dissociative amnesia, episodic memory is present and does not involve problems in procedural memory or in memory storage, as in Wernicke-Korsakoff Syndrome. The amnesia is reversible, including by hypnosis. The memory loss is for discreet periods of time, ranging from days to years, and usually for traumatic or stressful events, which it follows. Onset may be gradual or sudden. Those in the third or fourth decades of life are most often affected. Usually only one episode is involved, but multiple periods of lost memory are seen. Comorbidity occurs with conversion disorders, depression, alcohol abuse and bulimia nervosa. Personality disorders of histrionic, dependent or borderline type occur in a minority of patients.

Dissociative fugue

In this condition, in addition to the features of dissociative amnesia, there is purposeful travel beyond the usual everyday range and maintenance of basic self-care. Simple social interactions with strangers are usually preserved. The unconscious motivation (primary gain) may be to avoid arrest for criminal activities or intolerable stresses at home or at work.

This is effectively amnesia with wandering, with an inability to recall personal past history, sometimes combined with a partial or new identity. Memory of recent traumatic or stressful events may be lost. The differential diagnoses include: organic fugue, where basic self-care and activities of daily living are not characteristically preserved, and post-ictal states, where there is an absence of current stressors and travel is without purpose.

Dissociative stupor

In this disorder, voluntary movement is severely reduced but the individual responds to external stimuli in a normal way. In spite of apparent reduction in consciousness, the individual is neither sleeping nor unconscious.

Other dissociative disorders

Included in this ICD-10 category isGanser’ syndrome, which is characterized by approximate or ridiculous answers to questions (e.g. Elizabeth III is the Queen of England; a horse has five legs) and which occurs in the setting of diminished consciousness (an hysterical twilight state). There may also be somatic conversion signs and pseudohallucinations. The condition was originally described by Ganser in 1898 in three prisoners and initially viewed as malingering. It is nowadays considered to be very rare.

Also included in this category is multiple personality or, in DSM-IV-TR, dissociative identity disorder, where there exist within the person two, the commonest type, or more distinct personalities or personality states,at least two of which recurrently take full control of the person’ behaviour. Switches between personalities are usually rapid. No personality has any awareness of any of the others. Sometimes a personality will be that of the individual at an earlier age. Multiple personality has been recognized since the early 1900s and was well described in the 1957 film of the book entitled The Three Faces of Eve by Drs C.H. Thigpen and H.M. Cleckley. Sufferers may have a past history of childhood abuse. Some meet the criteria for dissocial personality disorder. Others have a history of substance abuse. It remains a controversial diagnosis, more often made in the USA than in the UK. It can be iatrogenic if reinforced during psychotherapy.

Reflecting the influence of culture, dissociative trance or possession disorder is more common in the East.

Predisposing and precipitating factors

Predisposing factors include severe childhood emotional trauma and abuse (often sexual), and a borderline personality disorder. The condition is usually triggered by severe psychological stress.

Conversion disorders

Conversion disorders are characterized by loss of or alteration in bodily function arising from psychological conflict or need, not explicable by a medical disorder. Symptoms are typically neurological, affecting the voluntary nervous system. Typically, one or two neurological symptoms are seen. They are not, however, under voluntary control, as the individual is not conscious or aware of their psychological basis, i.e. the individual is not intentionally producing symptoms or otherwise malingering. Such symptoms arise via the unconscious defence mechanism of displacement. This group of disorders was central in the history of the development of psychoanalytic theory.

Classically, symptoms in dissociative (conversion) disorders are of symbolic significance and have an unconscious motivation or primary gain, such as relief from intolerable intrapsychic conflict or the reduction or loss of anxiety, which may present as a calm acceptance (la belle indifférence) of what appears to be a serious disability. Internal conflicts are kept away from awareness. The gain is primarily psychological, not financial, legal or social. Thus, an individual who is fearful both of battle and of being thought a coward may solve this conflict unconsciously by developing paralysis of the lower limbs, symbolizing the conflict. Similarly, individuals who unconsciously do not wish to see or hear what is going on may develop hysterical blindness or deafness. In the past ‘hysterical fits’ (dissociative seizures) in females were related to sexual ‘frigidity’. Such individuals may also achieve secondary gain from their symptoms, such as attention, care and affection from others, including relatives, by the manipulation of relationships and by avoiding unwanted everyday tasks or situations, i.e. adopting the advantages of the sick role.

Theoretically, in dissociative and conversion disorders the motivation is unconscious, whereas in malingering it is conscious. In clinical practice, however, such a differentiation may be less clear cut and it is often better to assess the degree of unconsciousness of motivation, which itself may vary over time.

Family and early background, as well as cultural factors, may determine the choice of hysterical symptoms, which may be modelled closely on symptoms experienced during a childhood illness, when the rewards of attention resulting from the sick role may have been learnt. Similarly, an individual may develop a conversion symptom when a close relative develops similar symptoms, such as paralysis of one side as the result of a stroke.

In the past hysterical fainting by females was common, but is now a rare event. Similarly, in developed countries, gross paralysis of the limbs is now less common, whereas more subtle neurological conversion symptoms are more apparent. Gross conversion symptoms, however, still occur frequently in some developing countries.

Neurophysiological studies show that although an individual with a conversion disorder may say that no feeling in an area is experienced, corresponding cortical evoked responses to tactile stimulation may be detected in the brain using an electroencephalogram.

Individuals with conversion disorder (e.g. with limb paralysis) are suggestible and may ‘take up their beds and walk’ on suggestion from a respected other. Alternatively, they may respond to physiotherapy, thereby unconsciously saving face.

Epidemiology

The age of onset is usually in adolescence or early adulthood, but it may appear for the first time during middle age or even later. However, it should be emphasized that symptoms suggestive of a conversion disorder occurring in middle age or beyond are very likely to be caused by organic illness. Although conversion disorder was considered common several decades ago, it is now much more rarely encountered and is considered to be more common in women than in men. Most cases are seen in neurological or orthopaedic practice, or in military settings, especially at times of war, and it may be more common in lower socioeconomic groups. The incidence is falling in developed countries, but remains high in developing countries.

Clinical features

To summarize the above, symptoms have a primary gain, which reduces anxiety and helps resolve emotional conflict. They may be associated with secondary gain (e.g. the attention of others), and symptoms may be symbolic and determined by, or modelled on, cultural, family or early background factors. Classically, symptoms may be calmly accepted (la belle indifférence), although in practice this is not frequently seen. However, the diagnosis is not dependent on the demonstration of gain or indifference. There is usually only one conversion symptom present in one episode of conversion disorder. Symptoms include:

• Sensory symptoms. These are incompatible with peripheral or central nervous system disorders and may include anaesthesias and paraesthesias, especially of the extremities. For example, it can produce ‘stocking and glove’ anaesthetic areas of the hands and feet (Figure 11.1), but it should be noted that this particular presentation can also result from certain organic causes, notably diabetic neuropathy and treatment with amiodarone.

• Special sense organ symptoms. These may include deafness and either unilateral or bilateral blindness or tunnel vision.

• Motor signs are summarized in Figure 11.2.

Figure 11.1 • Typical areas of sensory loss in conversion disorders.

Figure 11.2 • Common motor symptoms of conversion disorders.

Conversion symptoms may be distinguished from organic symptoms by their variability, their nature– which often reflects an individual’ concept of anatomy and physiology – and by their inconsistency withknown anatomy and physiology. For example, individuals with hysterical aphonia are able to use the same muscles to cough that they would normally use to speak. Individuals with hysterical blindness may avoid colliding with objects. Areas of anaesthesia may be increased by suggestion from a doctor during an examination. Apparently paralysed extensor muscles of one leg may contract when the individual is asked to lie supine and raise the opposite leg.

History taking should concentrate on eliciting precipitating stress factors, and a close relative or acquaintance should also be interviewed, as this may help elucidate,among other matters,the individual’ use of the sick role. Physical examination and investigations should be completed quickly and, if normal, the physical symptoms themselves thereafter ignored.

Differential diagnosis

This includes any undiagnosed physical disorder, especially one that presents with vague multiple somatic symptoms, such as systemic lupus erythematosus or multiple sclerosis. Undiagnosed physical disorders may be either difficult to diagnose (e.g. haemangioblastoma of the cerebellum or tumours of the foramen magnum) or not routinely considered (e.g. myasthenia gravis or acute intermittent porphyria). Recent studies, in contrast to some of those in the past, have found low rates of development of neurological disorders (range 1–3%).

Conversion symptoms can occur in somatization disorder and, more rarely, in schizophrenia. Other diagnoses to be considered include hypochondriacal disorder, and also malingering where symptoms are consciously produced.

Aetiology

Predisposing factors

There is little evidence in favour of a genetic predisposition to conversion disorders.

It was Freud who initially used the term conversion. He had observed the French neurologist Charcot producing conversion hysteria in susceptible individuals by the use of hypnosis and even suggestion. The mechanisms underlying this condition have been unsatisfactorily sought since. Freud saw these disorders as arising from mental or psychological energy and anxiety being repressed and converted into physical symptoms, which were often suggestive of a neurological disease, and which resulted in avoidance of emotional conflict and thus a reduction in intrapsychic anxiety. The conflict is between instinctual impulses, e.g. aggressive or sexual, and inhibition against their expression.

A premorbid histrionic, dependent, passive-aggressive or antisocial personality disorder may be present in up to one-fifth of cases. Traits of suggestibility and increased capacity to dissociate may predispose towards the development of conversion symptoms.

Learning theory explains conversion disorders in terms of classical conditioning.

Either previous physical disorders and/or exposure to such disorders in others may be a predisposing factor by providing a model for the choice of conversion symptom. For instance, dissociative convulsions (pseudoseizures) are more likely to occur in those who suffer from epilepsy, as this provides a model for their symptoms and also they have learnt the advantages of the sick role as a result.

The increased incidence of conversion disorder in the young and immature may reflect the fact that they have only recently emerged from the privileged dependent state of childhood. Similarly, it has been suggested that the greater proportion of women sufferers apparent in the past perhaps reflected their overall greater dependence on men. In keeping with this theory, the ratio of female to male sufferers has fallen considerably in recent decades.

Precipitating and perpetuating factors

Precipitating factors include severe stress, such as the recent death of a close relative, whose physical symptoms may be modelled by the patient, and at times of war. In fact, experience of warfare suggests that everyone is capable of developing a conversion disorder. Head injury and temporal lobe epilepsy have also been suggested as precipitating factors. Impaired action generation with decreased activity in the left dorso-lateral pre-frontal cortex has also been found.

The condition is perpetuated by secondary gain and the advantages of the sick role (see above).

The possibility of financial gain, such as in compensation neurosis, may also perpetuate the disorder.Table 11.4 summarizes the aetiology of conversion disorders.

Table 11.4 Aetiology of conversion disorders

Predisposing factors	Childhood experience of illness
Precipitating factors	Physical illness, e.g. epilepsy, Guillain–Barré syndrome
	Negative life events
	Relationship conflict
	Modelling of others’ illness
Perpetuating factors	Behavioural responses, e.g. avoidance, disuse, reassurance seeking
	Cognitive responses, e.g. fear of worsening, fear of serious disease